HERNE, Germany—The TNF blocker infliximab (Remicade®,Centocor, Inc) slows the structural progression typically seen in ankylosing spondylitis (AS), but inhibiting TNF does not appear to stop radiographic damage, according to 4-year follow-up data reported in Rheumatology.¹

"There is some radiographic progression after 2 and 4 years of infliximab therapy in AS patients," conclude researchers led by Xenofon Baraliakos, MD, of the Rheumazentrum Ruhrgebiet, in Herne, Germany.

Comparison to historical controls suggest that infliximab slows progression

Researchers examined conventional radiographs of the cervical and the lumbar spine of 33 AS patients at baseline, 2, and 4 years of infliximab therapy. They compared these results to historical controls from the Outcome in Ankylosing Spondylitis International Study (OASIS) cohort of AS patients who were treated conventionally.

The X-rays were scored by the modified Stokes ankylosing spondylitis spinal score (mSASSS). Using mSASSS >e;2, they defined both definite baseline damage when at least one syndesmophyte was seen and definite radiographic progression as a change from 0 or 1 to syndesmophytes or ankylosis.
 
The mean change in mSASSS score over 4 years in the infliximab-treated patients was 1.6 ± 2.6 units (P = .001), compared with a mean change of 4.4 units over a similar period in the historical control group. The investigators suggest that this "would indicate that the speed of progression of structural change may be reduced by infliximab therapy."

Definite radiographic progression was evident in 30.3% of infliximab-treated patients after 2 years of treatment and was more severe in those who already had radiographic damage at baseline.

The investigators suggest that, "overall radiographic progression in AS patients could have been even less if anti-TNF therapy [had] been initiated in an earlier phase of disease before radiographic damage had occurred."

Anti-TNF drugs still good choice for AS

"This is the first study to provide 4-year follow-up data on radiographic progression in AS patients receiving anti-TNF therapy and it suggests, albeit with only 33 patients, that infliximab may decelerate the pace of radiographic progression," Walter P. Maksymowych, FRCPC, told CIAOMed. Dr. Maksymowych is professor of medicine and consultant rheumatologist at the University of Alberta, in Edmonton, Canada. "The comparison is with a historical cohort that demonstrated greater mean progression over 4 years." He pointed out that obtaining more definitive data may be impossible because a randomized study would require patients to remain on control therapy for at least 2 years, the minimum time required to demonstrate significant change in patients receiving standard therapies.

The study does have some limitations, noted CIAOMed editorial board member Désirée van der Heijde, MD, PhD, professor of rheumatology at the University Hospital of Maastricht, in The Netherlands.

"There is a comparison of data from the literature scored by one person with scores obtained from a cohort of patients treated with TNF blockers scored by another person who is aware of the fact that all these patients are being treated with infliximab, so this is an uncontrolled observation," Dr. van der Heijde said.

Drs. Maksymowych and van der Heijde both stressed the clinical efficacy of TNF inhibition in AS. "Rheumatologists should still prescribe these drugs to AS patients, as they are very effective on signs and symptoms, function, quality of life, bone mineral density, and working ability," Dr. van der Heijde concluded. 

Reference

1.  Baraliakos X, Listing J, Brandt J, et al. Radiographic progression in patients with ankylosing spondylitis after 4 yrs treatment with the anti-TNF-α antibody infliximab. Rheumatology. 2007;46:1450-1453.